WHAT IS THE ENGINE OIL CLEARANCE OF THE CONNECTING ROD BEARING AND ITS CAP BOLT.NIT TIGHTENING TORQUE?

  • Tiny
  • Edgyona10
  • 1987 MERCEDES BENZ 260E
  • 33,400 MILES

The connecting rod bearings are due for replacement

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Wednesday, September 14th, 2011 AT 9:35 AM

10 Replies

  • Tiny
  • Jacobandnickolas
  • EXPERT
  • 68,402 POSTS

The bearings shouldn't need replaced at 33K miles. Are you getting a knocking from the engine? Has the oil been changed on a regular basis?

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Wednesday, September 14th, 2011 AT 4:49 PM
  • Tiny
  • Edgyona10
  • MEMBER

The engine oil pressure was such too low. Zero reading as engine warms up. An oil change is not followed at its regular changing intervals.

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Thursday, September 15th, 2011 AT 5:09 AM
  • Tiny
  • Jacobandnickolas
  • EXPERT
  • 68,402 POSTS

Can you hear the rod bearings knocking? My concern is that it may just be a bad oil sending unit. You may want to check oil pressure with a mechanical gauge to confirm the pressure is very low. As far as clearance between the bearings and crank, you are looking at thousands of an inch. You need plasta-gauge to check if they are bad.

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Friday, September 16th, 2011 AT 12:15 AM
  • Tiny
  • Edgyona10
  • MEMBER

There's no knocking noise whatsoever. Since we've got to change the conrod bearing, we will be using plasti-gauge to initially check the clearances. May we please know the oil clearance tolerance and the tightening torque of the conrod bolts. Thanks.

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Friday, September 16th, 2011 AT 4:32 AM
  • Tiny
  • Edgyona10
  • MEMBER

By the way, what is the specific lenght measurement of the oil pump relief valve spring. Sorry for the mis typing of mileage run, it should be 68,912.

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Friday, September 16th, 2011 AT 4:42 AM
  • Tiny
  • Jacobandnickolas
  • EXPERT
  • 68,402 POSTS

Connecting rod journals diameter 1.8880 - 1.8884 inches or 47.955 - 47.965mm

Torque:
Step 1. 22 ft lbs
Step 2. Angle tighten 90 degrees

I don't have the length of the relief spring. All I can find on that is it is set to release at 71 psi

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Friday, September 16th, 2011 AT 5:07 AM
  • Tiny
  • Edgyona10
  • MEMBER

Thanks for the info, it will best serve us if the measurement has to be taken on the flattened plasti-gauge rather than taking the difference between the diameter of the big end bore against the diameter of the crankpin journal. I reasoned out that I dont have caliper and bore measuring tools. May I please know the oil clearance dara, your help is so much appreciated. Thanks.

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Friday, September 16th, 2011 AT 2:21 PM
  • Tiny
  • Jacobandnickolas
  • EXPERT
  • 68,402 POSTS

Oil clearance? I'm not sure I understand.

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Saturday, September 17th, 2011 AT 2:56 AM
  • Tiny
  • Edgyona10
  • MEMBER

Means the required clearance between the connecting rod bearing and its corresponding crankpin journal.

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Saturday, September 17th, 2011 AT 6:49 AM
  • Tiny
  • Jacobandnickolas
  • EXPERT
  • 68,402 POSTS

That would be the tolerance of the bearing. It should be.010

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Saturday, September 17th, 2011 AT 6:13 PM

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